Machining Setup's with Few Comments

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Carrdo
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Re: Machining Setup's with Few Comments

Post by Carrdo » Tue May 29, 2018 11:08 pm

If you can shows us (with photos) of how to setup the Quorn to do end mill "gashing" or the grinding of the "third facet" (as I call it) on the end of a two flute end mill, I am all ears (and eyes). No one has been able to show me how to do this (yet) on the Quorn.

I can do it on the surface grinder with the commercial end mill and Washburn fixture which I made but with the Quorn how ????

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Carrdo
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Re: Machining Setup's with Few Comments

Post by Carrdo » Tue Jun 19, 2018 6:17 pm

A case of reduction.

Starting with an 8" wide, metre long piece of 0.3 mm (0.012") thick annealed spring steel sheet, a number of 5/8" (+) wide strips were sheared from the parent metal. Following this, a further number of 1/8" (+) wide pieces were sliced from each of the sheared strips ending up with a further number of 1/8" wide by 5/8" long bits of spring steel.

Say it fast and it sounds simple but it is anything but that.

First problem, have you ever tried to find annealed spring steel in a small (workshop) quantity?. It is unobtainium here in North America. Blue tempered (hard) spring steel yes but for this job the spring steel had to be formed with two 90 degree bends so the spring steel had to be in a soft (annealed) condition.

The 8" wide metre long piece you see came from far offshore and I am not certain that it is annealed spring steel although it was advertised as such. It does spring though. Then, the way it was shipped, it came all kinked but luck, this time, was on my side as I was able to carefully hand work it back to the condition seen in the first photo.

Since I don't have a shear or anything like that, I had to take a trip to Richard's place and his commercial shear produced the 5/8" wide strips which were straight and had a very a clean edge. First problem solved but the shear wouldn't slice off 1/8" wide pieces and leave a clean straight edge which was what I needed.

I am not going to show any photos of the secondary slicing operation as it was done out of desperation more than anything else and is more than a little dangerous but it involved using my DuMore hand grinder mounted in the tool holder of the 7" bench shaper. The DuMore grinder spins a Dremel cutoff wheel at 38,000 RPM and all I can say is that you had better know what you are doing. It did the job but left a few edge burrs which will be handled by the special setup in the surface grinder as, in the end, everything has to be kept dead square and parallel. The surface grinder setup looks simple but it was another learning experience to determine how these tiny little pieces could be made to sit square in the holding fixture.

The second photo shows the various stages of the spring steel to bring it to the finished part (which is the black one).

To be continued.
Attachments
383 An Annealed 8 Inch (200 mm) Wide Piece of Sheet Spring Steel 0.012 Inch (0.3 mm) Thick.jpg
384 The Spring Steel Sheet First Sheared Into Five Eighth Inch (+) Wide Strips and Then Sliced Into One Eigth Inch (+) Wide Pieces.jpg

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Carrdo
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Re: Machining Setup's with Few Comments

Post by Carrdo » Tue Jun 19, 2018 7:33 pm

For the spring steel part forming I made up a two part male and female forming die to be used in my small bench arbor press. The die material only had to be mild steel as the spring steel was formed in the annealed (soft) condition.

Just a lot of careful hand sawing, filing and polishing until the two parts of the forming die were the correct shape and closely matched one another.

To my advantage, I was able to use a previously made holding fixture from another project.
Attachments
386 The Arbor Press Setup to Form the Spring Steel Blank.jpg
387 The Female Half of the Forming Tool.jpg
388 The Male Half of the Forming Tool.jpg

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Carrdo
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Re: Machining Setup's with Few Comments

Post by Carrdo » Wed Jul 11, 2018 4:48 pm

The finished spring steel friction clips and thumbscrews.

They have all been "gun blacked" by a very simple method shown to me and others at a TSME meeting by Bill Huxhold. Just one of a million incredible things he knows and does.

No commercial or otherwise gun blacking solution/process is involved at all.
Attachments
389 The Finished Spring Steel Friction Clips and Thumbscrews.jpg

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Carrdo
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Re: Machining Setup's with Few Comments

Post by Carrdo » Tue Jul 17, 2018 4:11 pm

An operation to produce an accurate narrow deep slot.

This is one of the most difficult and frustrating machining tasks one can encounter.

The slot in question had to be 1/8" wide and 1-3/32" deep in commercially bought gauge stock material which, even in its non heat treated state, is not that easy to machine. To make matters worse, the slot had to be exactly on size, centered, straight, not bell mouthed and have a good finish.

Gauge stock was used as one is supposed to be able to be machine it without it distorting in any way. Not quite true!

How was it done.

Rough out the blank, mill it dead square and parallel leaving it 0.015" oversize.

Ink and layout the central slot leaving the layout lines 0.015" smaller than the finished slot width on each side with the bottom layout line being the full slot depth.

The secret is to be able to bandsaw out as much material as possible up to (but not over) the layout lines. Use a fine (32 wavy tooth) blade, the sharper the better. The secret is not to push the bandsaw blade, just let it cut by itself and use one's fingers only to steady and guide the blank against the fence of the bandsaw. It takes forever in this material but if the above is followed the blade will make a straight cut. Good lighting is essential.

Cut down each side of the slot and then the bandsaw blade can be used to remove the center strip piece (if any is left). Also, I can use the bandsaw blade somewhat like a milling cutter to roughly square the slot end.

At this point, the gauge stock had bell mouthed 0.006".

I let the gauge stock blank sit at this point for a day (which probably did nothing) after which I cleaned up the slot in the mill with a 3/32" wide previously used side tooth slitting saw as I had one.

This was followed with a new 1/8" wide side tooth slitting saw to finish the slot. Use plenty of cutting oil, run the saw very slowly and feed down into the slot very slowly. One also has to have a very good saw arbor as, with a job like this, the saw cannot waver at all or it will cut an oversize slot.

The result was an on size, central and very straight slot as determined by the test square piece seen in the first photo.

While the central slot is dead straight, the gauge stock blank is still 0.005" bell mouthed at the open end of the slot. So now, all subsequent machining operations have to be set up from the central slot.
Attachments
390 A Narrow Deep Slot.jpg
391 The Setup in the Bandsaw to Initially Rough Out the Slot Opening.jpg

pete
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Re: Machining Setup's with Few Comments

Post by pete » Tue Jul 17, 2018 4:29 pm

Nicely done Carrdo. One trick I picked up from a few welders mentioning it to me was to drop the part from 2"-3" up onto concrete or steel multiple tmes to help release built in stresses. Beating it with a hammer can help do the same if the parts oversize enough to machine off the apprentice marks. :-) I'm unsure if it helps or I'm just wasting my time, but a few cycles through the kitchen oven at the self cleaning setting for temperature and in between a few over night stays in the deep freeze is "supposed" to help relieve built up stresses as well.

John Hasler
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Re: Machining Setup's with Few Comments

Post by John Hasler » Tue Jul 17, 2018 7:34 pm

Self-cleaning ovens get to 500C. That's enough for annealing.

Harold_V
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Re: Machining Setup's with Few Comments

Post by Harold_V » Wed Jul 18, 2018 1:12 am

John Hasler wrote:
Tue Jul 17, 2018 7:34 pm
Self-cleaning ovens get to 500C. That's enough for annealing.
While 500°C can temper (draw) ferrous heat treated items, it is far too low to anneal. I make mention for those who may have need for true annealing. For that, you must exceed 750°C (each alloy has its own requirements). The lower temperature (500°C) would likely help in lowering internal stresses.

H
Wise people talk because they have something to say. Fools talk because they have to say something.

John Hasler
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Re: Machining Setup's with Few Comments

Post by John Hasler » Wed Jul 18, 2018 8:44 am

Yes, that's what I meant. It will fully anneal copper, though.

Harold_V
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Re: Machining Setup's with Few Comments

Post by Harold_V » Wed Jul 18, 2018 3:26 pm

John Hasler wrote:
Wed Jul 18, 2018 8:44 am
Yes, that's what I meant. It will fully anneal copper, though.
Albeit at the cost of considerable time. Higher temp is desirable.
"Copper annealing temperature
Generally annealing is done at greater than 1/2 of the melting point on the absolute temperature scale. Copper melts at 1083C = 1356K so the annealing is done at greater than 678K = 405C = 761F. However, it will take a fairly long time at the lower end of the range so it is more common to anneal at about 700 to 800C.
Annealing Copper Wire for Bonsai Use

www.evergreengardenworks.com/copperwi.htm"

I've annealed copper alloys, as well as gold and silver, both pure and alloyed. I don't rely on any given temperature, just get them dull red, then quench (not necessary to quench, it isn't the quench that makes them soft. Air cooling works just fine, but it's much slower). Gold, being extremely heavy, undergoes a remarkable change when thin sheet is annealed. It can't support its own weight when held parallel to the ground. The anode of pure gold I made for plating a railroad spike proved that to be true.

H
Wise people talk because they have something to say. Fools talk because they have to say something.

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Carrdo
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Re: Machining Setup's with Few Comments

Post by Carrdo » Thu Jul 19, 2018 2:53 pm

Closing the rectangle after surface grinding. You can see where I am heading with this.
Attachments
392 Closing the Rectangle After Surface Grinding.jpg

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